Most conventional locks use tumblers to control a lock; in such locks, a plurality of springs and tumblers are installed in and between the cylinder body and the plug member of a lock cylinder; when a correct key is inserted in the lock cylinder, the tumblers will be pushed to a splitting line, after which the plug member can be rotated to unlock the lock.
Such a conventional lock is usually unable to prevent picking by a lock picker. Generally, a lock picker uses a feeling method or a scanning method to pick a lock by lifting all the tumblers one after another or by lifting all the tumblers together, and then rotating the plug member.